Rockaway Townsquare mall has a new tenant that is becoming a hot property for shopping centers and downtown landlords. This tenant, next door to a J.C. Penney department store, doesn’t sell clothes, shoes or cosmetics. Instead, customers pay $20 to be locked in a room for an hour, and solve riddles in order to “escape.”

Remember the frozen yogurt explosion, when every block had a frozen yogurt shop? Or the boutique fitness bulge that brought Pilates studios and spin classes to strip malls? Get ready for the escape room boom.

Escape rooms — interactive entertainment venues where people pay to be locked in a room and must solve riddles to be released — are expanding rapidly in North Jersey and around the country. The rooms over the past year have gone from novelty to next big thing, with landlords welcoming them as a way to fill space in malls and downtowns at a time when traditional retailers are closing stores.

North Jersey has at least a dozen escape rooms, and the owners of many of them have new locations in the works. The company behind the Rockaway Townsquare location, Escape the Mystery Room, said its mall locations typically draw 20,000 visitors a year, and they expect that number to grow as more people learn about escape rooms.

“Retail real estate is transitioning,” said Curtis Nassau of Ripco Real Estate in Lyndhurst. “Owners are expanding their view of what can constitute a healthy retail tenant — whether it's medical, fitness, entertainment or experiential.”

Experiential retail, where customers spend their money on experiences rather than on clothes or consumer goods, is seen as the savior of suburban shopping malls in the era of online shopping.

“Shopping center space is continually going to be more and more directed toward entertainment, on the big scale or small scale,” said Chuck Lanyard, president of The Goldstein Group retail real estate brokerage in Paramus. Lanyard said he is seeing many kinds of new entertainment options moving into retail spaces, from trampoline rooms to indoor skydiving facilities, such as the I Fly location proposed for Route 4 in Paramus.

“I think the best part of it,” Lanyard said, “is it allows everybody to turn their cellphone off and spend an hour with their family.”

Stephanie Cegielski, a spokeswoman for the International Council of Shopping Centers, said the council is starting to see more escape rooms opening in malls, joining other forms of experiential retail, such as rock climbing walls and virtual reality rooms.

Escape the Mystery Room executives say malls are welcoming them with open arms. The company is creating a national chain of mall-based escape rooms and believes malls are the perfect locations for escape rooms to thrive.

“Malls are interested in transforming themselves into a comprehensive entertainment venue, not just a shopping place. We help them add that additional dynamic,” said Chetan Patel, vice president of operations at Escape the Mystery Room. The Georgia-based company has 13 escape rooms in operation, all in malls, with five more set to open within 30 days. Two additional New Jersey mall locations, in Woodbridge and Cherry Hill, are scheduled to open later this year.

Freehold-based Amazing Escape Room LLC, which operates five escape rooms in New Jersey, including one in Montclair, is looking for space in Paramus. Escape Room NJ, which has locations in Hackensack and Madison, is expanding to Pompton Plains and Warwick, N.Y.

Escape entrepreneurs say the trend has room to grow because there is a huge source of potential customers out there: the more than 60 percent of the population who haven’t been to an escape room yet, or haven’t even heard of them.

“We feel really confident based on the metrics that there is a tremendous amount of growth left” as more people discover escape rooms, Patel said. He also is confident that his company will be able to attract repeat visitors.

Jeff Sherfer, who with his partners founded Escape Room NJ, was operating a kids’ party space in Hackensack and saw the need for interactive activities for adults.

“There’s a big deficit for adult activities now,” he said. “Once you’re done going to clubs and drinking, how many restaurants can you go to and have the same birthday party experience over and over again?” Escape rooms, he said, can be used for adult birthdays, family groups, corporate team building exercises or date-night outings. “I can have a 10-year-old in there and I can have an 85-year-old in there, and they’ll have fun and interact and communicate,” he said.

Theme parks, resorts, and cruise ships have jumped on the escape room trend as well, said Jennifer Braverman, president of Transworld Trade Shows, LLC, which is hosting its second escape room conference and trade show in Niagara Falls next week.

Transworld hosts an annual trade show for operators of Halloween haunted houses and attractions. It noticed that many of those businesses were opening escape rooms and created a trade show for them. The show attracts puzzle and game designers, special-effects companies and even insurers that specialize in escape rooms and other experiential retail. Transworld’s first escape room show last year drew some 1,700 people and this year’s attendance is expected to reach 2,000, Braverman said.

North Jersey escape room owners say their rooms emphasize problem solving, rather than scary situations. Most of the rooms have an emergency release or call button in case a participant wants to exit the game early. At Escape the Mystery Room in Rockaway Townsquare mall, the walls of the room don’t reach the ceiling. The 2 feet of open space above the walls is intentional, to make the locked room feel less claustrophobic.

Most escape rooms charge $18 to $25 per person. Group rates vary based on the number of players.

The expansion trend in North Jersey is fueled by demand. Local operators said they are booked weeks in advance. At Escape Room NJ in Hackensack on a recent Thursday, owner Jeffrey Sherfer juggled two cellphones that were ringing constantly with groups booking rooms, while ushering players into and out of the two escape rooms at his venue.

Eli Rozenberg, 23, of Monsey, N.Y., emerged with a group of relatives from The Other Side Room, which requires players to solve a detective mystery, and gave the experience a thumbs up. “It was very fun and very smart,” said Rozenberg, who said his group included players from age 12 to over 50. Rozenberg is a fan of escape rooms: He proposed to his wife in one,

But first-timers also were enjoying the experience. A group of seven employees from the Tenafly office of Keller Williams Realty chose Escape Room NJ for a team building exercise. “Everybody loved it,” said Keller Williams team leader Ana Enersen, after the group emerged from the room. The office does team building activities about every six months, and past events have included spa trips and a group personality test. They chose Escape Room NJ when they were looking for something different. “This is pretty different,” Enersen said.

Sherfer, Patel and other escape room operators believe they can keep their businesses from becoming a passing fad by changing their puzzles and theme rooms frequently and upgrading them with features such as virtual reality games and immersive theater experiences with live actors.

Sherfer plans to add live actors to the experience in his Pompton Lakes location, which is expected to open this fall.

Heidi Neufeld, regional operations manager of Freehold-based Amazing Escape Room LLC, said that company also is planning to add live actors to some of its rooms. But her company is hedging its bets and looking ahead to what they think could be the next big thing: hatchet throwing. It is preparing to open Bury the Hatchet game rooms in South Jersey, where teams of players will compete by throwing small hatchets at targets. “Google 'ax throwing,' ” she said. “It’s a thing.”